Ocular melanoma is an extremely rare form of cancer that affects the eye with an incidence of 5 per million adults. Although rare, it is the most common primary cancer of the eye in adults. Primary means that the cancer began at that site (in this case the eye) and did not spread there from another part of the body.
In most people, this cancer arises in a part of the eye known as the uveal tract. The uveal tract is the colored (pigmented) layer of tissue that is found beneath the white of the eye (sclera) and is composed of normally pigmented cells and blood vessels.
In the front of the eye, the uvea is made up of the colored part of the eye (iris) and a circle of muscle tissue (ciliary body) that releases a transparent fluid (aqueous humor) into the eye and helps to control the shape of the lens. The largest area of the uveal tract is in the back part of the eye (choroid) which is located beneath the retina, the vision sensing portion of the eye.
In most instances, ocular melanomas arises within the choroid. Ocular melanoma arises from cells called melanocytes, which are the cells of the body that produce pigment. Ocular melanoma is a cancerous (malignant) tumor that can potentially spread (metastasize) to other parts of the body, most often to the liver. The exact cause of this disorder is unknown, but several risk factors have been identified.
Symptoms
The following factors seem to increase the risk of developing eye melanoma:
- a dark spot in the iris, which may grow
- displacement of the eye within the eye socket
- flashing lights in the visual field
- watery eyes
- blurry vision
- a loss of peripheral vision in one eye
Risk Factors
The following factors seem to increase the risk of developing eye melanoma:
- Eye color: People with blue or green eyes have a higher risk of developing ocular melanoma than those with brown eyes.
- Exposure to ultraviolet (UV) light: Exposure to UV light may increase the risk of conjunctival melanoma. This is a melanoma that occurs on the surface of the eye.
- Dysplastic nevus syndrome: In this condition, a person develops atypical moles, known as dysplastic nevi. These are different to ordinary moles. They have irregular borders, may contain several different colors, and often appear in clusters. Dysplastic nevi are more likely to develop into malignant melanomas than ordinary moles.
- Ethnicity: Eye melanoma is most likely to develop in white people.
Diagnosis
Early detection, diagnosis, and treatment of ocular melanoma are crucial for a good outlook.
Undergoing regular eye tests with a doctor who specializes in eye treatment, known as an ophthalmologist or optometrist, is the best way to detect eye melanoma early.
Treatment
Treatment for ocular melanoma depends on several factors, including the location, size, and type of tumor, as well as the person’s overall health.
If a melanoma lesion on the eye is small, a doctor may suggest monitoring rather than immediate treatment. Interventions may lead to some vision loss.
[1] https://rarediseases.org/rare-diseases/ocular-melanoma/
[2] http://www.ocularmelanoma.org/disease.htm
[3] https://www.cancer.ca/en/cancer-information/cancer-type/eye/statistics/?region=on
[4] https://saveyourskin.ca/ocumelcanada-about-ocular-melanoma/
[5] https://www.medicalnewstoday.com/articles/183858#diagnosis